This invention relates to camera exposure control circuitry, and more particularly to exposure control circuitry operative in response to a signal from an electronic flash device during flash photography operation.
In the case of flash photography with an electronic flash device, unless the main capacitor charge in the electronic flash device exceeds a given level, photography with appropriate exposure cannot be effected. It is therefore advantageous if the charged condition of the main capacitor is detected and a light emitting element in the camera viewfinder is flashed to notify the photographer of whether or not a desired photographic exposure is possible. Further, the exposure time for flash photography should be controlled at a given shutter speed (for instance 1/60 second) in synchronization with the firing of the electronic flash tube, especially where the shutter is a focal plane shutter. Accordingly, if the setting of the aforesaid shutter speed is automatically effected in response to the detection of the completion of the main capacitor charging, then there may be obtained many advantages in the practical application of a camera.